The use of front loaders for moving material using a tractor is known. For this purpose, front loaders can be mounted on or coupled to the tractor by means of a frame console provided on the tractor. The front loader usually has a lift arm assembly comprising a pair of transversely spaced, parallel lift arms, which are fixed together by a transverse torque tube and extend on the front end of the tractor, and are equipped with a suitable loading tool, for example a shovel, a gripper, a lifting fork, etc., wherein the lift arms and the front loader tool are usually actuatable by means of hydraulic or electric actuators. Parking stand devices can be provided on the lift arms of the front loader, which each comprise a parking support having an end pivotally coupled to the lift arm and can be pivoted into a parked position wherein it engages the ground or other support surface, in which said parking support can be locked. In the parked position, the front loader can be decoupled from the tractor and can be supported on the parking support surface in such a way that the lift arms are held in an upright coupling or decoupling position when the front loader is set down or parked, and so the front loader can be decoupled or coupled by releasing (or closing) the front loader locking mechanism and subsequently (or previously) simply manoeuvering the tractor.
A parking stand device of this kind is disclosed in WO 2008/070901 A1. The parking stand device disclosed there comprises a parking support, which is pivotably mounted on the arm of a front loader and can be pivoted out of an operating position (in which the front loader is coupled to the tractor) into a parked position (in which the front loader can be decoupled and set down or parked). An additional locking brace extends between the lift arm and the parking support and is mounted to the lift arm at one end so as to be pivotable relative to the lift arm and is guided at the other end so as to be displaceable along the parking support. The locking brace is furthermore connected to a locking bar, which extends along the parking support and implements a locking as soon as the parking support moves against a stop and reaches the parked position. A parking stand device of this kind is designed for an angular position—which can be preset and is nonetheless established—of the parking support with respect to the lift arm of the front loader, with the result that, given a constant presetting, the final parked position varies or is different depending on the tool coupled to the front loader or depending on irregularities in the ground. As a result thereof, after the front loader is decoupled, the front loader tilts into the parked position, which has been established by the presetting and set as a result of the tool and the ground conditions, and the interfaces on the front loader mast and on the vehicle frame can diverge in terms of the level thereof when coupled on again, which results in considerable manoeuvering work in order to couple the front loader. In addition, the aforementioned shape of the parking stand device is complex and has a great diversity of parts.
A further parking stand device is disclosed in EP 1 389 656 A1. Therein, a parking support having a locking brace extending between a front loader arm and a parking support is provided, wherein the parking support is provided with a snap-in tooth system and the locking brace is provided with complementary snap-in teeth on the free end. The snap-in teeth provided on the locking brace can be placed, via an actuating cylinder, in different positions on the snap-in tooth system and can be engaged therewith. As a result, an optimal angular position of the parking support with respect to the front loader lift arm can be set or the present circumstances with regard to the tool and the ground irregularities can be taken into account, and so the front loader also remains in the same parked position after the decoupling procedure, and therefore the height position of the interface on the front loader mast, when coupled again, is substantially unchanged from the height position during decoupling. The disadvantage in this case is that the snap-in tooth system and the snap-in teeth, in interaction with one another, engage into one another completely, i.e., over the full surface, only in an optimal locking position. Outside of this optimal locking position, the snap-in tooth system and the snap-in teeth engage into one another only over a portion of the surface or even only at points, whereby a high and, therefore, unfavourable, contact force on the snap-in teeth sets in, which can result in damage, on the one hand, or, on the other hand, requires a correspondingly high-strength and robust material formation.
The problem addressed by the invention is considered to be that of providing a variable parking stand device of the type mentioned at the outset, by way of which the aforementioned problems are overcome.